WO 2009/024755 A1 discloses an apparatus for induction heating and spray coating of the exterior surface of a pipe where the induction heating coil and coating applicator are located side by side around a longitudinal section of a pipe (or weld region of two adjoining pipe sections) of a particular diameter. The apparatus comprises separate stator and rotor frames, with the rotor frame being rotationally mounted to an end face of the stator frame so that the rotor frame can rotate relative to the stator frame. The stator frame is formed from two semicircular sections that are pivotally connected together at one end so that the stator frame can be opened to mount the section of pipe and closed around the outer diameter of the pipe. Electric conductors are disposed between the two end faces of the stator frame so that they surround the outer diameter of the section of the pipe within the stator. A coating applicator is mounted to the rotor frame, which is axially outboard of the stator frame, so that the applicator can be rotated around the pipe to coat the entire outer circumference while the rotor frame remains fixed in position, or is rolled along the axial length of the pipe. The coating applicator can also be moved longitudinally relative to the pipe while the stator frame is stationary.
One disadvantage of the apparatus in WO 2009/024755 A1 is that the coating applicator is located external to the induction heating coil along the axial length of the pipe, and the apparatus must be axially moved along the length of the pipe section to first coat and then heat a section of the pipe and/or first heat and then coat a section of the pipe.
The prior art heating and coating apparatus 800 shown in FIG. 1(a) through FIG. 1(f) solves the above disadvantage by locating permanently one or more fixed position coating head assemblies 810 fitted within the axial length (along the Z-axis) of the induction heating coil (not shown in the figures for clarity) surrounding a section of pipe 90 passing through the central opening of apparatus 800 as illustrated in FIG. 1(d).
In apparatus 800 the one or more coating head assemblies 810 are located within and attached to rotating inner carriage 820 that has an axial length of z1 as shown in FIG. 1(b). The inner carriage is driven and rotates around pipe 90 by means of a set of sprocket wheels 840 located on each side of the inner carriage. The sprocket wheels engage into chain slots 850 as shown in FIG. 1(e). Rotation of a commonly coupled drive shaft 830 results in similar rotation of the sprocket wheels causing engagement in chain guides and rotational movement of the inner carriage 820 and the one or more coating head assemblies 810 around the outer diameter of a pipe. The master drive shaft coupling 890 shown in FIG. 1(f) can be controlled via an electric or pneumatic motor, or other rotational driver. Apparatus 800 opens and then closes around the outer diameter of a pipe by “clam shell action” of lower apparatus halves 800a and 800b with the clam shell action created by the movement of cylinders and linkage bars 880 acting on hinge pivot points 870 and 871 for parting and joining of the lower apparatus halves at parting line 801 in FIG. 1(f). An induction coil is permanently located inside the main device frame in the form of a number of flexible water cooled conductors (not shown for clarity). The conductors would be located within the holes shown in inductor support bars 860 (as best seen in FIG. 1(d)) that are spaced around the perimeter of the main device frame. The induction coil electric circuit is made when closed and broken when opened by means of a series of electric wiping contacts 861 as shown in partial cross sectional FIG. 1(d) when the clam shell action described above takes place. Vertical plenum 812 provides a means to mechanically interface the apparatus 800 to other mechanical or structural devices not included in this description and may also allow means for ducting electrical supplies, cooling water and coating material supplies to the apparatus.
A disadvantage of apparatus 800 is that the combination of the permanently mounted one or more coating head assemblies 810 and permanently located induction heating coil assembly do not permit independent change of the coating head and/or coil assemblies from the apparatus structural frame and from the drive assembly for the coating head assemblies so that different configurations of coating head and/or coil assemblies can be substituted into the structural frame of the apparatus and/or the drive assembly for the coating head assemblies. Therefore the apparatus 800 in any one totally configured arrangement can only be used to heat and coat one particular outer diameter of pipe, which increases costs for a user of the apparatus if the user requires heating and coating of pipes having various diameters. A second disadvantage of apparatus 800 is that the electrical contacts 861 cannot easily be exchanged or replaced without removal of the electrical conductors and breakage of the water cooling circuit since the induction coil assembly can not be removed from apparatus 800 as a unitary assembly for direct access to the contacts and the contacts' mounting elements; whilst the contacts themselves form a permanently assembled part of the mechanical structure of the induction coil conductor and its associated water cooling path.
It is one object of the present invention to provide interchangeable axially aligned coating head and induction coil heating assembly tooling sets that can be inserted and removed as a cartridge from a common apparatus frame that contains the drive for the coating heads and other necessary support mechanisms; whilist the contacts themselves form a permanently assembled part of the mechanical structure of the induction coil conductor and its associated water cooling path.
It is another object of the present invention to provide a combined electric induction heating and coating apparatus for the exterior surface of a pipe where the electric induction heater and coating head assembly can be arranged relative to the drive for the coating heads so that pipes in a range of outer diameters can be accommodated within the same combined electric induction heating and coating apparatus using interchangeable tooling sets (cartridges) and coating head assemblies.
It is another object of the present invention to provide the ability to use the combined electric induction heating and coating apparatus in either a “heating only” mode or “coating only mode” independently, as well as a combined “heating and coating” mode by means of interchangeable tooling set (cartridges) for the induction coil and the coating head assemblies.
It is another object of the present invention to provide a method for establishing a high accuracy of heating temperature profile for the section of the pipe being heated by utilizing specifically designed and precise manufactured induction coil assemblies that are specific to the requirements of the heating process and can be interchanged for other specific induction coil assemblies to alter the performance of the combined electric induction heating and coating apparatus of the present invention to suit specific application requirements.
It is another object of the present invention to provide the ability to change the coating applicators or coating head assemblies both in arrangement and design to allow easily the adaption of the combined electric induction heating and coating apparatus of the present invention to different coating requirements.
It is another object of the present invention to provide the ability to change the heating induction coil arrangement and design to allow easily the adaption of the combined electric induction heating and coating apparatus of the present invention to different heating requirements.
It is another object of the present invention to allow a particular or any configuration of heating induction coil (or other type of inductor) and/or coating head assembly to be used for a range of applications, pipe outer diameters, pipe wall thicknesses, and coating requirements by simple adjustment or by more specific re-tooling or setting.
It is another object of the present invention to give flexibility of operation and improved maintainability of a combined electric induction heating and coating apparatus by making the electrical contacts of the induction coil (or other type of inductor) easily replaceable and of such a design that facilitates good life-time and operational efficiency.
It is another object of the present invention to provide a combined electric induction heating and coating apparatus that can be used in variable and changing angles of perspective relative to horizontal or vertical pipe position as required by the position of the pipe.